This progress report describes the state of a 4-year study of the role of endocrine, psychological, and social factors in sexual adjustment of couples in the age range 51-60 years. The basic first year study of long-married couples constitutes the bulk of this progress report. Completed in all phases, some of the analytical chemistry and data analysis remains to be done. Some initial work with the second and third year phases of this study are described, primarily with respect to subject recruitment. A spinoff study derived from the first year study is described concerning a hormonal correlate of marital pair-bonding. Husband-wife cortisol levels have been shown to be related to two personality measures: the MMPI Ego Strength Scale score and the Locke-Wallace Marital Adjustment Scale score. To further demonstrate this relationship, the diurnal cortisol profile of both marital partners is presently being assessed in a predictive attempt to relate this metameter to the aforementioned personality measures. The implications of this new study are briefly described.